Lens layout block device

ABSTRACT

This apparatus includes a unit for adhering an elastic seal to a lens holder, a unit for causing the lens holder, to which the elastic seal is adhered, to hold a lens, a pivotal arm, an arm driving unit for pivoting the pivotal arm, a clamp unit attached to the pivotal arm to be vertically movable to hold the lens holder, and a clamp driving unit for vertically moving the clamp unit. The pivotal arm is pivoted to sequentially adhere the elastic seal to the lens holder and hold the lens by the lens holder.

TECHNICAL FIELD

The present invention relates to a lens layout blocker.

BACKGROUND ART

Spectacle lenses (to be also referred to as lenses hereinafter) includedifferent types such as a single-vision lens, a multifocal lens, and aprogressive multifocal lens, and their diameters, outer diameters, lenspowers, and the like differ from one lens type to another. Hence, alarge number of types of lenses must be fabricated.

Conventionally, edging of such lenses is performed in accordance withthe following procedure. For example, assume that a single-vision lensis to be edged. When the prescription lens is determined, if it is anordinary prescription, a corresponding prescription lens is selectedfrom the stock lenses (mass-production products of the regularinventories).

If the prescription lens is a lens not available from the stock lenses(a custom-made article not available from the regular inventories), itis manufactured by the factory in accordance with the order. A stocklens has an upper surface (convex lens surface) and lower surface(concave lens surface) finished with predetermined lens curvatures(curves) on the basis of the optical design to have a predetermined lenspower, and is completed until the final step of a surface process suchas hardwearing coating or antireflection coating. Regarding acustom-made article, a lens material for it is prepared in advance inthe form of a semifinished product (semifinished lens blank). The lensmaterial is subjected to roughing-out, polishing, and the like inaccordance with the ordered prescription power, and then to a surfaceprocess, so it is used as the prescription lens.

Once a prescription lens is manufactured, it is horizontally stored in alens storing tray, together with a processing instruction slip, with itsconcave lens surface facing down, and is conveyed to an edging line. Theoperator takes out this prescription lens from the tray, places it onthe inspection table of a predetermined inspecting unit such as a lensmeter to check its lens power, cylinder axis, and the like. A processingcenter, the mounting angle of a processing jig (lens holder) withrespect to the lens, and the like (optical layout) are determined fromthe lens information, lens frame shape data, and prescription data abouta wearer. On the basis of this information, the lens holder is mountedto the processing center of the lens (blocking). The lens holder ismounted on an edger together with the lens. The lens is edged by a grindstone or cutter, thereby processing the lens into a shape conforming tothe shape of an eyeglass frame.

Conventionally, an optical layout and blocking for a lens, which areincluded in the pre-process for edging of the lens, are manuallyperformed by an operator using specialized devices. This process is veryinefficient and low in productivity, and hence becomes a serioushindrance to labor savings. In addition, since an operator must handlethe lens with great care so as not to soil, damage, and break it, asignificant burden is imposed on the operator. Also, when a lens holderwith a lens holding surface conforming to the curvature of theprescription lens is to be selected, the operator tends to erroneouslyselect a different type of lens holder easily. When the operator adheresan elastic seal to the lens holder, the urging force varies, anddefective adhesion occurs.

For these reasons, demands have recently arisen for the development ofan apparatus for single-vision lenses, and progressive multifocal lensesand multifocal lenses (ABS; Auto Blocker for Single Vision Lens, andABM; Auto Blocker for Multi-focus Lens), which is designed toautomatically perform an optical layout for a lens and lens blockingwith a lens holder, thereby improving operation efficiency. Thisapparatus will be referred to as a layout blocker hereinafter.

As the lens holder used for edging of the spectacle lens, for example,one disclosed in, e.g., Japanese Utility Model Laid-Open No. 6-024852and Japanese Patent Laid-Open No. 9-225798, are known. Such a lensholder is usually formed of a cylindrical body and has a concavespherical lens holding surface at its distal end face. When holding alens, a thin elastic seal is adhered to the lens holding surface inadvance, and is urged against the convex lens surface of the lens so asto be adhered to it. The lens holding surface has a large number of fineprojections, each with a triangular section, radially formed on itsentire edge, so that the tight bonding properties between the lenssurface and elastic seal is increased and rotation of the elastic sealis prevented.

When a lens is mounted on a conventionally known lens holder, it is thenmounted on an edging device together with the lens holder. The edge ofthe lens is edged by a grind stone or cutter, thereby processing thelens into a shape conforming to the shape of an eyeglass frame. Whenperforming edging, the lens holder that holds the lens is mounted on oneof two coaxial clamp shafts. The two surfaces of the lens are clamped bythe lens holder and the other clamp shaft. The two clamp shafts arerotated in one direction, and are simultaneously controlled, on thebasis of the lens frame shape data, to move in a direction perpendicularto the axis. Edging is thus performed with the grind stone or cutter.

The lens types are infinite since one lens power D (diopter) can becombined with convex and concave surface curves, and are actuallydetermined considering the optical aberration and inventory management.More specifically, a lens design in which the number of types of convexsurface curves is decreased while different concave surface curves areused is employed. For example, regarding a progressive multifocal lens,up to 8 types of lenses, ranging from a 2-curve lens to 9-curve lens,may be prepared. In the case of a single-vision lens, as it generallycopes with a wide range of power, for example, 12 types of lenses,ranging from 0-curve lens to 11-curve lens, are sometimes prepared.

The lens power D (Diopter) is expressed by a difference in curvaturebetween a convex surface curve D1 and a concave surface curve D2. In thesemi-finished lenses such as single-vision lenses or progressivemultifocal lenses, their lens powers are classified in accordance withonly the convex surface curves D1. For example, a single-vision lenswith a convex-surface lens power D of 4 is called a 4-curve lens, andits radius of curvature is calculated by D=(N−1)×1000/R (mm) where N isthe refractive index of the lens, which is 1.50 when the lens materialis diethyleneglycol bis allylcarbonate, which is used most generally,and R is the radius of curvature of the convex lens surface. Hence, inthe case of a 4-curve lens, when this value is substituted in the aboveequation, 4=(1.5−1)×1000/R yields R=125 mm. Similarly, in the case of a7-curve lens, it is converted into a radius of curvature of about 71 mm.In the case of an 11-curve lens, its radius of curvature is about 45 mm.

Conventionally, as the lens holders, to enable stable holding, speciallyprepared lens holders are used for individual lenses with different lenspowers, respectively, or two types of lens holders, i.e., one for ashallow curve and one for a deep curve, are used. When several types oflens holders having lens holding surfaces with different curvatures areprepared and are to be selectively used in accordance with the curvatureof the convex lens surface of the lens to be held, the number of typesof holders themselves increases, imposing problems in maintaining andmanaging them. With the method of using the two types of holders, i.e.,one for the shallow curve and one for the deep curve, a flexiblematerial (e.g., plastic) is used as the material of the holdersthemselves. Plastic, however, has a problem in its durability andprecision. All the lens holders need be fabricated with the same sizeregardless of the curvatures of their lens holding surfaces.Conventionally, the types of the holders are discriminated fromidentification symbols or numbers formed on the outer surfaces of thelens holders by engraving or the like. In this case, the operator mustform the identification symbols or numbers by engraving or the like.This operation is cumbersome. The operator must check the lens holder bymanually holding it. Moreover, if the identification symbol or numberbecomes unclear due to the soil and wear of the surface of the holderitself, defective engraving, or the like, it is difficult for theoperator to read it. Therefore, the operator must handle the lens holdercarefully. In particular, when this identification method is applied tothe layout blocker described above, the operator and sensor must be ableto discriminate the type of the lens holder easily and reliably.

In any case, in a layout blocking step before performing conventionallens edging, various types of operation steps must be performed by theoperator. These operations must be performed in a limited space,resulting in a very poor operation efficiency.

DISCLOSURE OF INVENTION

It is an object of the present invention to provide a lens layoutblocker for solving the conventional problems described above andmeeting their demands.

More specifically, it is the main object of the present invention toprovide a lens layout blocker which can automatically perform layout andblocking operations for a lens within a limited space.

It is another object of the present invention to provide a lens holderwhich can perform holding well and can be easily and reliablydiscriminated as to whether it is of the same type.

It is still another object of the present invention to provide a lenslayout blocker which automatically performs layout and blockingoperations for a lens in order to edge the lens, so the operability andproductivity are improved and labor savings are enabled.

It is still another object of the present invention to provide an urgingchange unit for a lens layout blocker, which can reliably adhere anelastic seal to a lens holder and adhere a lens to the elastic seal.

In order to achieve the above objects, there is provided an apparatusfor attaching a lens to a lens holder, characterized by comprising aunit for adhering an elastic seal to a lens holder, a unit for causingthe lens holder, to which the elastic seal is adhered, to hold a lens, apivotal arm, an arm driving unit for pivoting the pivotal arm, a clampunit attached to the pivotal arm to be vertically movable to hold thelens holder, and a clamp driving unit for vertically moving the clampunit, wherein the pivotal arm is pivoted to sequentially adhere theelastic seal to the lens holder and hold the lens by the lens holder.

According to another aspect of the present invention, there is provideda lens layout blocker characterized by comprising a holder supply unitfor holding a lens holder at a holder mounting position, conveying thelens holder to a seal adhering position, causing an elastic seal to beadhered to the lens holder at the seal adhering position and conveyingthe lens holder to a lens holding position, and causing a lens to beheld by the elastic seal at the lens holding position, the holder supplyunit comprising a pivotal arm, an arm driving unit for pivoting thepivotal arm within a horizontal plane, a clamp unit for holding the lensholder attached to the pivotal arm to be vertically movable, and a clampdriving unit for vertically moving the clamp unit.

According to still another aspect of the present invention, there isprovided a lens holder formed of a cylindrical member and having a lensholding surface formed of a concave spherical surface at a distal endthereof to hold a plurality of types of lenses with convex lens surfacesof different curvatures by an elastic seal adhered to the lens holdingsurface, characterized in that the plurality of types of lenses areclassified into a plurality of lens groups in which lenses with convexlens surfaces of similar curvatures form one army, and the lens holdercomprises a plurality of types of lens holders corresponding to the lensgroups, each of respective types of the lens holders serving to hold alens belonging to a corresponding lens group with an edge of a lensholding surface thereof.

According to still another aspect of the present invention, there isprovided a lens holder formed of a cylindrical member and having a lensholding surface formed of a concave spherical surface at a distal endthereof to hold a plurality of types of lenses with convex lens surfacesof different curvatures by an elastic seal adhered to the lens holdingsurface, characterized in that the plurality of types of lenses areclassified into a plurality of lens groups in which lenses with convexlens surfaces of similar curvatures form one group, and the lens holdercomprises a plurality of types of lens holders corresponding to the lensgroups, each of respective types of the lens holders having a lensholding surface a lens holding surface with a radius of curvature equalto or smaller than a minimum radius of curvature of a convex lenssurface of a lens belonging to a corresponding lens group.

According to still another aspect of the present invention, there isprovided a lens layout blocker for urging, at a seal adhering position,a lens holding surface of a lens holder against an elastic seal, thusadhering the elastic seal to the lens holding surface, and urging, at ablocking position, the elastic seal, adhered to the lens holding surfaceof the holder, against a lens, thus adhering the lens to the elasticseal, characterized by having a unit for urging the elastic seal,adhered to the lens holding surface of the lens holder, against the lenswith an urging force smaller than that with which the lens holdingsurface of the lens holder is urged against the elastic seal.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1(a) and 1(b) are front and rear views, respectively, of a lensholder used in an apparatus for attaching a lens to a lens holderaccording to the present invention;

FIG. 2 is a sectional view showing a state in which a lens is mounted onthe lens holder through an elastic seal;

FIGS. 3(a), 3(b), and 3(c) are an enlarged sectional view taken alongthe line III—III of FIG. 1, a view showing a lens holding surface, andan enlarged sectional view of this lens holding surface, respectively;

FIG. 4 is a front view of an ABS for a single-vision lens;

FIG. 5 is a plan view of the ABS in FIG. 4;

FIGS. 6(a), 6(b), and 6(c) are a sectional view of a holder storingcassette, a view of the same before being mounted on a chute, and a viewof the same mounted on the chute, respectively;

FIG. 7 is a sectional view of the central portion of the cassette awayfrom pin positions;

FIG. 8 is a view showing a lens holder transfer portion and a shuttermechanism;

FIG. 9 is a view showing a state in which an arris process for a lens isbeing performed;

FIG. 10 is a view seen from an arrow V of FIG. 9;

FIGS. 11(a) and 11(b) are a plan and front views, respectively, of aholder support mechanism;

FIG. 12 is a view showing lens holding operation performed by the holdersupport mechanism;

FIG. 13 is a view showing lens holding operation performed by the holdersupport mechanism;

FIGS. 14(a) and 14(b) are views showing centering operation for the lensholder performed by a centering mechanism;

FIG. 15 is a sectional view of a holder holding unit;

FIG. 16 is a view showing a relationship among seal positions, i.e., aholder mounting position A4, seal adhering position A5, lens holdingposition A6, holder transfer position A7, and stand-by position A8;

FIGS. 17(a) and 17(b) are views showing holding operation for the lensholder performed by a clamp unit;

FIG. 18 is a view showing operation performed when adhering an elasticseal to the lens holder;

FIG. 19 is a view showing operation performed when adhering a lens tothe elastic seal;

FIGS. 20(a) and 20(b) are views showing turn-on and turn-off operationsof a selector valve; and

FIG. 21 is a view showing the schematic arrangement of anotherembodiment of the present invention.

BEST MODE OF CARRYING OUT THE INVENTION

An apparatus for attaching a lens to a lens holder according to thepresent invention will be described in detail by way of embodimentsshown in the drawings.

FIGS. 1(a) and 1(b) are front and rear views, respectively, of a lensholder used in an apparatus for attaching a lens to the lens holderaccording to the present invention, FIG. 2 is a sectional view showing astate in which a lens is held by the lens holder through an elasticseal, and FIGS. 3(a), 3(b), and 3(c) are an enlarged sectional viewtaken along the line III—III of FIG. 1, a view showing a lens holdingsurface, and an enlarged sectional view of this lens holding surface,respectively.

Referring to FIGS. 1(a) to 3(c), reference numeral 1 denotes a spectaclesingle-vision lens 1 (to be merely referred to as a lens hereinafter)made of plastic and has a convex lens surface 1 a and concave lenssurface 1 b. The edge of the lens 1 is edged by an edger to conform tothe shape of a lens frame. When the lens 1 is a single-vision lens, asit generally copes with a wide range of power, as described above, it isprepared in 12 types, e.g., from a 0-curve lens to 11-curve lens. Tomake a lens holder 2 common, lenses 1 are classified into a plurality oflens groups each consisting of lens with similar curves, e.g., a firstlens group of 0- to 3-curve lenses, a second lens group of 4- to 6-curvelenses, and a third lens group of 7- to 11-curve lenses. Referencenumeral 3 denotes an elastic seal to be adhered to the lens holder 2.The convex lens surface 1 a of the lens 1 is held by the lens holder 2through the elastic seal 3.

The lens holder 2 is formed of a metal such as stainless steel into acollared cylindrical member which includes a fitting shaft portion 4,and a flange 5 and lens holding portion 6 integrally formed on the outersurface of the fitting shaft portion 4, closer to the distal end, and atthe distal end, respectively. The fitting shaft portion 4 has, forexample a length of 35 mm, an outer diameter of about 14 mm, and acentral hole 7 with a hole diameter of about 10 mm.

The flange 5 defines the fitting amount of the fitting shaft portion 4into a clamp shaft (to be described later), and has a thickness of about5 mm and an outer diameter of about 20 mm. A notched groove 8 is formedin the outer surface of the flange 5 to serve as a rotation preventiveportion that prevents rotation of the lens holder 2 with respect to theclamp shaft. A taper surface 8 a is formed on that opening portion ofthe notched groove 8 which is opposite to the lens holding portion 6,and is open outward so the fitting shaft portion 4 can be fitted on theclamp shaft easily.

The lens holding portion 6 is formed on the outer surface of the distalend of the fitting shaft portion 4, and has a thickness and outerdiameter substantially equal to those of the flange 5. A gap of about 5mm is formed between the lens holding portion 6 and flange 5. Thatsurface of the lens holding portion 6 which comes into tight contactwith the elastic seal 3 forms a concave spherical lens holding surface 9corresponding to the convex lens surface 1 a of the lens 1. If theradius of curvature of the lens holding surface 9 is larger than that ofthe convex lens surface 1 a, only the central portion of the lensholding surface 9 comes into contact with the convex lens surface 1 a,while the peripheral portion thereof does not come into contact with it.Then, the lens 1 is held unstably. On the contrary, if the radius ofcurvature of the lens holding surface 9 is smaller than that of theconvex lens surface 1 a, only the peripheral portion of the lens holdingsurface 9 comes into contact with the convex lens surface 1 a, while thecentral portion thereof does not come into contact with it. Thus, thelens 1 is held stably, and misalignment or the like can be prevented.

According to this embodiment, lens holders 2 with lens holding surfaces9 of different radii of curvature are prepared for lens groups,respectively. A lens holder 2 used for the first lens group of 0- to3-curve lenses described above is set as a 4-curve holder. A lens holder2 used for the second lens group of 4- to 6-curve lenses is set as a7-curve holder. A lens holder 2 used for the third lens group of 7- to11-curve lenses is set as a 11-curve holder. More specifically, the lensholders 2 include types corresponding in number (three types) to thelens groups. Each lens holder 2 has a lens holding surface 9 with aradius of curvature smaller than that of the convex lens surface 1 a ofthe lens 1 belonging to the corresponding lens group (regarding a lenswith 11 curves, a lens holder with the same curves as those of theconvex lens surface 1 a is used), to abut against the convex lenssurface 1 a of the lens 1 at the peripheral portion. In this manner,when the curvature of the lens holding surface 9 of the lens holder 2 isformed such that the curvature of the lens holding surface 9 is largerthan that of the convex lens surface 1 a of the lens 1 for each lensgroup, the lens 1 can be held mostly at the peripheral edge portion ofthe lens holding surface 9, as shown in FIG. 2. Note that only the radiiof curvature of the lens holding surfaces 9 are different, and exceptfor that the structures of the lens holders 2 are completely the same.If a difference in radius of curvature between the convex lens surface 1a and lens holding surface 9 is large, the degree of adhesion betweenthese two surfaces is low. Therefore, the smaller this difference, themore desirable.

A large number of fine projections 10 are radially formed on the entirelens holding surface 9 in order to increase the adhesion bond strengthwith the elastic seal 3. Each fine projection 10 has an isoscelestriangular section. Hence, a wall surface 10 b in the rotationaldirection of the lens holder 2 and a wall surface 10 c opposite to itform slants of the same angle of inclination (e.g., 45°) with respect toa vertex 10 a of the projection 10 as the boundary. When the slants havethe same angle in this manner, the elastic seal 3 comes into tightcontact with the two slants evenly. As the contact area increases, theappropriate flexibility and deformability of the seat are utilized, sothat the lens holding force can be increased. Since the elastic seal 3comes into press contact with the two slants of the same angle ofinclination evenly, an unbalance rotation force is canceled and is notgenerated. Therefore, the rotational shift of the elastic seal 3 thatdecreases the holding precision of the lens does not occur.

A rotation preventive portion 11 is formed on the outer surfaces of theflange 5 and lens holding portion 6 to engage with the engaging portionof a holder storing cassette 31 (to be described later) that stores thelens holder 2. The rotation preventive portion 11 is a groove formed bycutting part of the outer surfaces of the flange 5 and lens holdingportion 6 from a direction perpendicular to the axis. The rotationpreventive portions 11 and 8 are formed to be phase-shifted from eachother by 180° so they are back to back.

A member 13 for discriminating the type of the lens holder 2 is fittedin the lens holder 2 on the proximal end of the fitting shaft portion 4by press fitting. One end face of the member 13 forms substantially onesurface together with the proximal end face of the lens holder 2. Themember 13 is formed of a synthetic resin into a cylindrical membercolored in a required color. The color of the member is as follows. Forexample, for a 4-curve holder, the member 13 is colored white. For a7-curve holder, the member 13 is colored red. For a 11-curve holder, themember 13 is colored blue. Therefore, by seeing the color of the member13, the operator can discriminate at a glance whether the lens holder 2is a 4-, 7-, or 11-curve holder.

As the elastic seal 3, one which is formed of thin rubber with athickness of about 0.5 mm to 0.6 mm into a ring shape with an outerdiameter (about 22 mm) larger than that of the lens holding surface 9and an inner diameter (about 8 mm) smaller than the hole diameter of thelens holder 2, and is coated with an adhesive mass on the two surfacesis used.

Supply of the lens holder, supply of the elastic seal and lens to thisholder, and edging of the lens will be briefly described with referenceto FIGS. 4 to 10.

FIG. 4 is a front view of an ABS for a single-vision lens, FIG. 5 is aplan view of the same, FIGS. 6(a), 6(b), and 6(c) are a sectional viewof a holder storing cassette, a view of the same before being mounted ona chute, and a view of the same mounted on the chute, respectively, FIG.7 is a sectional view of the central portion of the cassette away frompin positions, FIG. 8 is a view showing a lens holder transfer portion,FIG. 9 is a view showing a state in which an arris process for a lens isbeing performed, and FIG. 10 is a view seen from an arrow V of FIG. 9.

Referring to FIGS. 4 to 6, an ABS 20 is set adjacent to the edger (notshown), has a holder conveying unit 22 formed on a base 21, a holderholding unit 23, a seal supply unit 24, a lens supply unit 25, a lensmeasuring device 26, and the like, and adopts a batch method ofsequentially processing 12 types (0- to 11-curve lenses) ofsingle-vision lenses with different convex surface curves in a randommanner.

The holder conveying unit 22 serves to supply three types of lensholders 2, 4-, 7-, and 11-curve holders to the holder holding unit 23,and has a holder supply mechanism 28 and holder support mechanism 29.

The holder supply mechanism 28 has three chutes 30 which are inclined atsuch an angle (e.g., 20°) that the lens holders 2 can slide on them bytheir own weights in the supply direction (a direction of an arrow 27 ofFIG. 5) of the lens holder 2, and are arranged parallel to each other inthe widthwise direction. Three holder storing cassettes 31 each storinga necessary number of (e.g., 42) lens holders 2 for each type aredetachably set upstream of the chutes 30 at the same angle as that ofthe chutes 30.

Referring to FIG. 6, each cassette 31 is formed of a metal, a syntheticresin, or the like into a thin, rectangular hollow body with two openends. Thus, the cassette 31 stores the lens holders 2 that are alignedin a line while the rotation preventive portions 11 are set in onedirection. An opening 33 is formed in an upper plate 32 of the cassette31 throughout the entire length. That portion of the lens holder 2 whichis closer to the proximal end than the flange 5 projects upward from thecassette 31 through the opening 33. Therefore, the member 13 can bevisually confirmed from above the cassette 31. When different types oflens holders 2 are mixedly stored in the cassette 31, they can bechecked at a glance. Also, erroneous mounting of the cassette 31 can beprevented. In other words, since the cassette 31 itself is identified bythe color of the member 13, a mistake that a certain cassette iserroneously set on a chute other than a chute where it should be, and amistake that a certain cassette is set across a plurality of chutes canbe prevented.

The width of the opening 33 is set to be slightly larger than the outerdiameter of the fitting shaft portion 4 of the lens holder 2. Theopening 33 slidably supports the lower surface of the flange 5. Theupper plate 32 is formed with different heights such that its one plateportion 32 a is slightly higher than its other plate portion 32 bthrough the opening 33 by almost the thickness of the cassette 31. Anend edge 32 a 1 of one plate portion 32 a is inserted in the rotationpreventive portion 11 of the lens holder 2. An inverted L-shaped bracket34 to be inserted in the rotation preventive portion 11 is fixed to thelower surface of the plate portion 32 a. This sets the direction of thelens holder 2 and prevents free rotation of the lens holder 2.

In the cassette 31, a pair of removal preventive pins 35 for preventingremoval of the lens holder 2 are disposed near the downstream opening soas to be movable to the left-and-right direction. These pins 35 areconnected to each other at their lower ends through a tension coilspring 36 and are biased in directions to come close to each other.Thus, the pins 35 are normally in contact with the lens holding portion6 to prevent the lens holder 2 from being removed. When the cassette 31is mounted on the chute 30, the pins 35 move in directions to separatefrom each other against the tension coil spring 36, thereby unlockingthe lens holder 2. The pins 35 are moved in the separating directions byan appropriate member 37 provided to the chute 30, as shown in FIG.6(c).

FIG. 7 is a sectional view of the central portion of the cassetteseparated from the pin positions. This cassette is different from thatin FIG. 6 in that it does not have the pair of removal preventive pins35 shown in FIG. 6.

The lens holders 2 in the cassette 31 slide on the holder storingcassette 31 and chutes 30 by their own weights. When the lens holders 2are sequentially discharged one by one by a shutter mechanism 38, theyare supported by the holder support mechanism 29 shown in FIGS. 5 and 8.

Referring to FIGS. 4 and 8, the shutter mechanism 38 has a pair ofstopper pins 39 for locking a first lens holder 2A by normally closing adischarge port 30 a of the chute 30, and an air cylinder 40 forvertically moving the stopper pins 39. When the air cylinder 40 isdriven by a supply signal from a controller (not shown), the lens holder2 is discharged from the chute 30. More specifically, when the aircylinder 40 is driven to move the stopper pins 39 downward so as to beretreated from the path of the chute 30, the first lens holder 2A isreleased from the stopper pins 39, so it is discharged from thedischarge port 30 a of the chute 30 by its own weight and moves onto aterminal end 30 b. The terminal end 30 b is set with a small angle ofinclination in order to decrease the slide speed of the lens holder 2and to decrease the impact produced when the lens holder 2 abuts againsta stopper 47 (to be described later) of the holder support mechanism 29.When the first lens holder 2A passes, the stopper pins 39 are movedupward to restore to the initial state. Thus, after sliding on thechutes 30 until the positions of the stopper pins 39, a second lensholder 2B is locked by the stopper pins 39, and serves as a new firstlens holder. This operation is repeated so the lens holders 2 areautomatically supplied one by one. The chute 30 is formed substantiallyidentical to the cassette 31, and is fixed on the base 21. Sensors 41(FIG. 4) for detecting the absence/presence of the lens holders 2 areattached to two portions, i.e., the downstream and intermediateportions, of the chute 30. The upstream sensor 41 is turned on when thenumber of lens holders 2 left in the chute 30 is 9, and prompts theoperator to replenish. The downstream sensor 41 is turned on when thenumber of lens holders 2 left in the chute 30 is 1, and stops the layoutblocker.

Referring to FIGS. 5, 8, and 11, the holder support mechanism 29 isdisposed on the base 21 to oppose the terminal end of the chutes 30, andhas a stage 43 which is movable in the back-and-forth direction of theABS 20 (direction of the arrow Y of FIG. 5) to reciprocally move betweenterminal end positions A1, A2, and A3 of the chutes 30 and a holdermounting position A4. The stage 43 is movably held by a pair of left andright rails 44 and a ball screw 45 which are formed on the base 21. Whena driving motor 46 is driven to rotate the ball screw 45, the stage 43moves along the rails 44 and ball screw 45. The terminal ends 30 b ofthe chutes 30 are positioned at the terminal end positions A1, A2, andA3 of the respective chutes 30.

A stopper 47 for receiving the lens holder 2 supplied to the terminalend 30 b of the chute 30, a pair of holder hands 48A and 48B forsupporting the lens holder 2, and an air cylinder 49 for actuating theholder hands 48A and 48B in synchronism to move in directions to beclose to and separate from each other are disposed on the upper surfaceof the stage 43. One holder hand 48A is formed of a rod-like member witha circular section, and holds the rotation preventive portion 11 of thelens holder 2 with the outer surface of its distal end. The other holderhand 48B is formed of a rod-like member with a rectangular section, andhas a V-shaped recess 50 in that side surface of its distal end whichopposes the lens holder 2. The recess 50 holds the outer surfaces of theflange 5 and lens holding portion 6 on that side of the lens holder 2which is opposite to the rotation preventive portion 11.

When the lens holder 2 is to be supplied, the stage 43 described abovehas moved in advance to the terminal position of that chute of the threechutes 30 to which the lens holder 2 is to be supplied, i.e., theposition A1, and waits there with the holder hands 48A and 48B beingopen (FIG. 12). When the lens holder 2 is supplied onto the terminal end30 b of the chute 30, the stopper 47 receives it, and the pair of holderhands 48A and 48B are closed to clamp it (FIG. 13). After that, theclamped lens holder 2 is conveyed to the holder mounting position A4,and centering of the lens holder 2 is performed.

Referring to FIG. 14, a centering mechanism 153 is disposed at theholder mounting position A4 to perform centering of the lens holder 2supported by the holder hands 48A and 48B. The centering mechanism 153is constituted by an elevating table 154 and an air cylinder 155 forvertically moving the elevating table 154. The upper surface of theelevating table 154 has a comparatively shallow recess 56 with a holediameter slightly larger than the outer diameter of the lens holdingportion 6 of the lens holder 2. A circular projection 157 is formed atthe center of the recess 156, and has a diameter slightly smaller than acentral hole 7 (FIGS. 1 and 3) of the lens holder 2. The elevating table154 is usually located substantially immediately below the lens holder 2to be separate from it (FIG. 14(a)). In centering the lens holder 2,when the air cylinder 155 is driven to move the elevating table 154upward (FIG. 14(b)), the recess 156 receives the lens holding portion 6of the lens holder 2, and the projection 157 fits in the central hole 7so the center of the lens holder 2 and that of the projection 157coincide with each other, thereby centering the lens holder 2. At thistime, the air cylinder 49 is deenergized to make the pair of the holderhands 48A and 48B flexible, thus enabling centering, so the lens holder2 is held to be movable in the left-and-right and back-and-forthdirections. After the lens holder 2 is centered, the elevating table 154moves downward successively to restore to the original initial position,thus ending centering.

Referring to FIG. 5 and FIGS. 15 to 17, the holder holding unit 23 isdisposed, on a side of the holder support mechanism 29, in a spacebetween the seal supply unit 24 (FIG. 5) and lens supply unit 25. At theholder mounting position A4, when the holder holding unit 23 receivesthe lens holder 2 centered from the holder support mechanism 29, itconveys the lens holder 2 to a seal adhering position A5 to adhere theelastic seal 3 to the lens holding surface 9 of the lens holder 2 itholds. After that, the holder holding unit 23 conveys the lens holder 2to a lens holding position A6, so the lens 1 is held by the elastic seal3. The holder holding unit 23 has a pivotal arm 160 (FIG. 15), a clampunit 161 attached to the distal end of the pivotal arm 160 to hold thelens holder 2, an arm driving motor (arm driving unit) 162 for pivotingthe pivotal arm 160 within a horizontal plane, a clamp air cylinder(clamp driving unit) 163 for vertically moving the clamp unit 161, andthe like.

The pivotal arm 160 is fixed to the upper end of a vertical rotatingshaft 165 standing upright on the base 21. The rotating shaft 165 isdisposed in a cylinder 166, standing upright on the base 21, to berotatable through radial bearings 167 and thrust bearing 168. A toothedpulley 169 is fixed to the lower end of the rotating shaft 165. Thedriving motor 162 is vertically fixed to an attaching member 170 formedon the base 21, with its output shaft 171 facing up. The output shaft171 is connected to a shaft 172 through a coupling 173. The shaft 172has a toothed pulley 174. A timing belt 175 extends between the pulleys174 and 169. When the driving motor 162 is driven to rotate the outputshaft 171, this rotation is transmitted to the rotating shaft 165through the coupling 173, shaft 172, pulley 174, timing belt 175, andpulley 169, so it can pivot the pivotal arm 160 within a horizontalplane. The pivot angle of the pivotal arm 160 is 300° in thisembodiment.

The clamp unit 161 is constituted by a cylindrical main body 82 to fiton the fitting shaft portion 4 of the lens holder 2, a holder fixingmechanism 83 for fixing the lens holder 2 to the main body 82 to preventit from removing, and the like. The main body 82 is fixed to the lowerend of a holding shaft 85 disposed to the distal end of the pivotal arm160 to be vertically movable and rotatable. The holder fixing mechanism83 has a holder fixing member 84 axially supported by a support pin 86,formed on the main body 82, to be pivotal in the direction of an arrow87 in FIG. 15, and the like. The holder urging member 84 fixes the lensholder 2 to the main body 82 by urging, has an urging portion 84 a atits lower end to urge the fitting shaft portion 4 of the lens holder 2,is disposed in an elongated hole 88 formed in the outer surface of themain body 82 and long in the axial direction, and is biased by a tensioncoil spring 89 counterclockwise in FIG. 13. Thus, usually, the urgingportion 84 a projects to the outside of the main body 82. This allowsthe lens holder 2 to be fitted in the main body 82 easily.

Furthermore, the holder fixing mechanism 83 has an air cylinder 90 foroperating the holder fixing member 84. The air cylinder 90 is attachedto the outer surface of the main body 82 with its operational rod 90 aopposing the holder fixing member 84. When the fitting shaft portion 4of the lens holder 2 is fitted in the main body 82, air is supplied tothe air cylinder 90 to actuate it. Thus, the movable rod 90 a urges theholder fixing member 84 to pivot it clockwise against the tension coilspring 89. Therefore, the urging portion 84 a of the holder fixingmember 84 urges the fitting shaft portion 4 of the lens holder 2 againstthe inner surface of the main body 82, thereby preventing the lensholder 2 from being removed.

The shaft 85 extends through an outer cylinder 94 fixed to the distalend of the pivotal arm 160 to be vertically movable and rotatable. Theupper end of the shaft 85 is connected to the clamp air cylinder 163through a coupling 95, and the lower end thereof extends through asleeve 102, disposed in the lower portion of the interior of the outercylinder 94, to be rotatable and vertically movable. The coupling 95 isconstituted by a columnar first coupling 95A fixed to the movable rod 63a of the air cylinder 163, and a cylindrical second coupling 95Bconnected to the first coupling 95A through a connection pin 96. Thecoupling 95 rotatably axially supports the upper end of the shaft 85with bearings 97 disposed in the second coupling 95B, and prevents theshaft 85 from dropping from the second coupling 95B with a set screw 98.The two ends of the connection pin 96 are slidably supported by an innercylinder 100 arranged in the outer cylinder 94 to project upward. Thisprevents rotation of the second coupling 95B. A pair of guide holes 101for guiding the connection pin 96 are formed in the wall portions of theinner cylinder 100 to be long in the axial direction. When the aircylinder 163 is driven to move the movable rod 163 a downward, the clampunit 161 is moved downward together with the shaft 85.

A driving motor 105 for pivoting the clamp unit 161 is set on the uppersurface of the pivotal arm 160 to face down. The driving motor 105serves to pivot the clamp unit 161 in accordance with the angle ofcylinder axis. An output shaft 105 a of the driving motor 105 isconnected to the upper end of a driven shaft 107 through a coupling 106.The driven shaft 107 is rotatably axially supported by bearings 108provided to an attaching member 110, and a small-diameter gear 109 isfixed to its intermediate portion. The attaching member 110 is fixed tothe pivotal arm 160. A transmission shaft 111 is disposed on a side ofthe driven shaft 107 to be parallel to it. The transmission shaft 111 isrotatably axially supported by bearings 112 provided to an attachingmember 115. A toothed pulley 113 is fixed to the upper end of thetransmission shaft 111, and a large-diameter gear 114 to mesh with thesmall-diameter gear 109 is fixed to the intermediate portion of thetransmission shaft 111. The attaching member 115 is fixed to the pivotalarm 160.

A toothed pulley 116 is disposed at the intermediate portion of theshaft 85 to correspond to the toothed pulley 113. A timing belt 117extends between the pulleys 113 and 116. The toothed pulley 116 isdisposed between the inner cylinder 100 and sleeve 102 to be rotatablethrough bearings 119, and is attached to the shaft 85 through splinefitting to be slidable relative to it. Hence, a groove 120 long in theaxial direction is formed in the outer surface of the shaft 85. Aprojection to slidably fit in the groove 120 projects from the innersurface of the toothed pulley 116. Therefore, rotation of the drivingmotor 105 is decelerated by the gears 109 and 114, and is transmitted tothe shaft 85 through the toothed pulleys 113 and 116 and timing belt117, to pivot the clamp unit 161 through the angle of cylinder axis.

An origin sensor 121 for positioning the shaft 85 at the position oforigin and a limit sensor 122 for limiting the pivot range of the shaft85 to 360° are disposed on the outer cylinder 94.

An arm fixing unit 127 is attached to the cylinder 166 through anattaching plate 128. A rotation preventive member 129 is fixed to thelower surface of the pivotal arm 160 to correspond to the arm fixingunit 127. Upon pivot motion of the pivotal arm 160, when the clamp unit161 is moved to the lens holding position A6 and is stopped there, thearm fixing unit 127 temporarily fixes the pivotal arm 160 at this pivotposition, to prevent rotation of the clamp unit 161 when the clamp unit161 is urged against the lens 1. An air cylinder is used as this armfixing unit 127, and is fixed to the attaching plate 128 with itsmovable rod 127 a facing up. An inverted V-shaped engaging member 130 isattached to the upper end of the movable rod 127 a. A V-shaped groove129 a is formed in the lower surface of the rotation preventive member129, and engages with the engaging member 130 when the clamp unit 161moves to the lens holding position A6 and stops there.

As shown in FIG. 16, the holder mounting position A4, the seal adheringposition A5, the lens holding position A6, and a holder transferposition A7 are formed to be located on one circumference with arotation center O of the pivotal arm 160 as the center and a radiuscorresponding to the distance to the clamp unit 161. The holder mountingposition A4 is where the clamp unit 161 receives the lens holder 2 fromthe holder support mechanism 29 and holds it. The seal adhering positionA5, holder transfer position A7, and lens holding position A6 areshifted from the holder mounting position A4 counterclockwise by 120°,230°, and 270°, respectively. The seal adhering position A5 is where theelastic seal 3 is adhered to the lens holder 2 held by the 1clamp unit61. The lens holding position A6 is where the lens 1 is held by the lensholder 2, held by the clamp unit 161, through the elastic seal 3. Theholder transfer position A7 is where the lens holder 2 (held by theclamp unit 161) that holds the lens 1 is transferred to a convey robotso it is supplied to the edger. A stand-by position A8 where the clampunit 161 is set in the stand-by state is formed between the holdermounting position A4 and lens holding position A6.

When the clamp unit 161 is to hold the lens holder 2, the pivotal arm160 is pivoted to move the clamp unit 161 to above the holder mountingposition A4, as shown in FIG. 17 (FIG. 17(a)). When the clamp unit 161is stopped above the holder mounting position A4, the air cylinder 163(FIG. 15) is driven to move the shaft 85 downward, and the main body 82of the clamp unit 161 is fit on the fitting shaft portion 4 of the lensholder 2 from above (FIG. 17(b)).

Subsequently, the air cylinder 90 is driven to pivot the holder fixingmember 84 clockwise against the tension coil spring 89, so the urgingportion 84 a of the holder fixing member 84 is urged against the fittingshaft portion 4. When the holder arms 48A and 48B of the holder supportmechanism 29 are opened to release the lens holder 2, the lens holder 2is held by the clamp unit 161. Thus, transfer of the lens holder 2 fromthe holder support mechanism 29 to the clamp unit 161 is ended. Theclamp unit 161 moves upward again, to convey the lens holder 2 it holdsto the seal adhering position A5 with the pivot motion of the pivotalarm 60.

Referring to FIGS. 4 and 5, the seal supply unit 24 serves tointermittently supply the elastic seal 3 to the seal adhering positionA5, and is disposed at the seal adhering position A5 to oppose theholder supply mechanism 28 through the holder support mechanism 29. Theelastic seal 3 is loaded in a roll loader 142 in the form of a roll 141wound around a shaft 140. In this roll 141, the elastic seals 3 arealigned in a line on a mount 253 (FIG. 18) at predetermined gaps, andtheir upper surfaces are covered with a protector paper 254. Eachelastic seal 3 is supplied to the seal adhering position A5 as theprotector paper 254 is separated from it.

When the elastic seal 3 is supplied to the seal adhering position A5 andis stopped, the clamp unit 161 is moved, upon pivot motion of thepivotal arm 160, to above the seal adhering position A5, and is stopped.Subsequently, the clamp unit 161 moves downward to urge the lens holdingsurface 9 of the lens holder 2 against the upper surface of the elasticseal 3, so the projections 10 bite the elastic seal 3. The clamp unit161 is moved upward, so the elastic seal 3 is separated from the mount253 and is adhered to the lens holding surface 9. When the elastic seal3 is adhered to the lens holding surface 9, the pivotal arm 160 pivotsthrough a predetermined angle counterclockwise in FIG. 5 to move thelens holder 2 held by the clamp unit 161 to the lens holding positionA6. During this movement, whether the lens holder 2 and elastic seal 3are present or not is detected. When the lens holder 2 is moved to thelens holding position A6 and is stopped, it is moved downward to urgethe elastic seal 3 adhered to the lens holder 2 against the lens 1supplied to the lens holding position A6, so that the elastic seal 3comes into tight contact with the lens 1. Therefore, the lens 1 is heldby the lens holder 2 through the elastic seal 3. FIG. 2 shows thisstate. A lens support unit 145 (FIG. 15) for supporting the lens 1supplied by the lens supply unit 25 (FIG. 5) is disposed at the lensholding position A6.

The urging force with which, at the blocking position A6, the elasticseal 3 adhered to the lens holding surface 9 of the lens holder 2 isurged against the lens 1 to adhere the lens 1 to the elastic seal 3 issmaller than the urging force with which, at the seal adhering positionA5, the lens holder 2 is urged against the elastic seal 3 to adhere theelastic seal 3 to the lens holding surface 9. This switching of theurging force is performed by an urging force change unit 255. Switchingof the urging force by the urging force change unit will be described inmore detail with reference to FIGS. 18 and 19.

Referring to FIGS. 18 and 19, reference numeral 240 denotes an aircylinder; and 241, a support column 2 vertically moved by the aircylinder 240. The pivotal arm 50 is pivotally disposed on the uppersurface of the support column 241. Reference numeral 244 denotes a shaftfor axially supporting the pivotal arm 160.

The urging force change unit 255 has the air cylinder 240, an air supplysource 256 for supplying compressed air to the air cylinder 240, aselector valve 258 connected to the air supply source 256 through a pipe257, pipes 259 and 260 for connecting the selector valve 258 and aircylinder 240 to each other, and the like. The support column 241 is setand fixed to the outer end of a piston rod 261 of the air cylinder 240.

The selector valve 258 is turned on/off by a solenoid, and has acylinder 258A, a spool 258B slidable in the cylinder 258A, and acompression coil spring 258C for biasing the spool 258B in a directionto project from the cylinder 258A, as shown in FIG. 20. The cylinder258A has five ports 262 a to 262 e, and the spool 258B has two annulargrooves 263 a and 263 b. The port 262 a is connected to the air supplysource 256, and the ports 262 b and 262 c form an exhaust port throughwhich the compressed air returning from the air cylinder 240 isexhausted to the atmosphere. The ports 262 d and 262 e are connected toan upper chamber 240 a and lower chamber 240 b of the air cylinder 240through the pipes 259 and 260, respectively.

When the selector valve 258 is OFF as shown in FIG. 20(a), the spool258B is held by the force of the compression coil spring 258C to projectfrom the cylinder 258A. In this OFF state, the ports 262 a and 262 ecommunicate with each other through the annular groove 263 a, the port262 b is closed, and the ports 262 c and 262 d communicate with eachother through the cylinder 258A. When the selector valve 258 is drivenby a driving signal from the controller and is switched to the ON stateshown in FIG. 20(b), the spool 258B is retracted into the cylinder 258Aagainst the compression coil spring 258C. In this ON state, the ports262 a and 262 d are connected to each other through the annular groove263 a, the ports 262 b and 262 e are connected to each other through theannular groove 263 b, and the port 262 c is closed.

The upstream end of the pipe 259 is connected to the port 262 d of theselector valve 258, and the downstream end thereof is connected to thatchamber (upper chamber) 240 a of the air cylinder 240 which is above apiston 240A. This downstream end of the pipe 259 also has a speedcontroller 264 for controlling the flow velocity with which thecompressed air in the upper chamber 240 a is exhausted.

The pipe 259 also has high-pressure and low-pressure branch pipes 259Aand 259B midway along it. A selector valve 265 is connected to thehigh-pressure branch pipe 259A, while a pressure reducing valve (fluidpressure switching means) 266 and check valve 267 are connected to thelow-pressure branch pipe 259B.

The upstream end of the other pipe 260 is connected to the port 262 e ofthe selector valve 258, and the downstream end thereof is connected tothat chamber (lower chamber) 240 b of the air cylinder 240 which isbelow the piston 240A. This downstream end of the pipe 260 also has aspeed controller 268 for controlling the flow velocity with which thecompressed air in the lower chamber 240 b is exhausted.

A pressure (main pressure) P of the compressed air supplied from the airsupply source 256 to the pipes 259 and 260 through the selector valve258 is, e.g., 5 kgf/cm², and is reduced to, e.g., 3 kgf/cm² by thepressure reducing valve 66.

The selector valve 265 is fixed to the support column 241, and is turnedon/off by the driving operation of an air cylinder 270 different fromthe air cylinder 240. In seal adhesion of urging the lens holder 2against the elastic seal 3 so the elastic seal 3 is adhered to the lensholding surface 3, the selector valve 265 is held in the ON state (FIG.18) At this time, v the selector valve 258 is also switched to the ONstate. In the ON state, the high-pressure branch pipe 259A is open, andthe compressed air from the air supply source 256 flows through the port262 a of the selector valve 258, the annular groove 263 a, the port 262d, the high-pressure branch pipe 259A, the selector valve 265, and thespeed controller 264 to be supplied to the upper chamber 240 a of theair cylinder 240. In lens adhesion of urging the elastic seal 3 adheredto the lens holder 2 against the lens 1 so the lens 1 is adhered to theelastic seal 3, the selector valve 265 is held in the OFF state (FIG.19) At this time, the selector valve 58 is held in the ON state. Whenthe selector valve 265 is switched to the OFF state, the high-pressurebranch pipe 259A is disconnected, and air from the air supply source 256flows through 262 a of the selector valve 258, the annular groove 263 a,the port 262 d, the low-pressure branch pipe 259B, the pressure reducingvalve 266, the check valve 267, and the speed controller 264 to besupplied to the upper chamber 240 a of the air cylinder 240.

The air cylinder 270 switches the selector valve 265. Also, when theclamp unit 51 is moved to the blocking position A6 and stopped, the aircylinder 270 temporarily fixes the pivotal arm 160 at this pivotposition. Accordingly, when the elastic seal 3 is urged against the lens1, the pivotal arm 160 is prevented from pivoting to be positionallydisplaced. The air cylinder 270 has a cylinder body 271 fixed to thesupport column 241, and a piston rod 272 extending through the cylinderbody 271. The piston rod 272 has an actuating member 273 at its lowerend to turn on/off the selector valve 265. A locking member 274 with aninverted V-shaped upper surface is attached to the upper end of thepiston rod 272. To correspond to the locking member 274, a rotationpreventive member 276 with a V-shaped groove 275 is fixed to the lowersurface of the pivotal arm 160. The rotation preventive member 276 isattached to such a position that, when the clamp unit 161 moves to abovethe blocking position A6, it opposes the locking member 274.

Referring to FIG. 18, upon pivot motion of the pivotal arm 160, theclamp unit 161 is moved above the seal adhering position A5 and stopped,to adhere the elastic seal 3 to the lens holder 2. At this time, sincethe selector valve 265 is held in the ON state, the compressed airsupplied from the air supply source 256 flows through the port 262 a ofthe selector valve 258, the annular groove 263 a, the port 262 d, thehigh-pressure branch pipe 259A, the selector valve 265, and the speedcontroller 264 to be supplied to the upper chamber 240 a of the aircylinder 240. The supplied air pushes down the piston 240A to urge thelens holder 2 against the elastic seal 3. At this time, the compressedair in the lower chamber 240 b flows through the pipe 260 and thenthrough the port 262 e of the selector valve 258, the annular groove 263b, and the port 262 b to be exhausted to the outside from an exhaustpipe 280.

The urging force with which the lens holder 2 is urged against theelastic seal 3 is 5 kgf/cm², which is equal to the preset pressure ofthe air supply source 256. Air supplied from the air supply source 56 isalso supplied to the low-pressure branch pipe 259B, and is reduced to 3kgf/cm² by the pressure reducing valve 266. As the high-pressurecompressed air from the high-pressure branch pipe 259A is added to thedownstream of the check valve 267, this pressure-reduced air will notopen the check valve 267.

After the lens holding surface 9 of the lens holder 2 is urged againstthe elastic seal 3 so the elastic seal is adhered to it, the selector 2valve 58 is switched to the OFF state. The compressed air from the airsupply source 256 flows through the port 262 a of the selector valve258, the annular groove 263 a, the port 262 e, the pipe 260, and thespeed controller 268 to be supplied to the lower chamber 240 b of theair cylinder 240. The compressed air in the upper chamber 240 a flowsthrough the speed controller 264, the low-pressure branch pipe 259B, thecheck valve 267, the pressure reducing valve 266, the port 262 d of theselector valve 258, and the port 262 c to be exhausted to the atmospherefrom the pipe 280. Hence, the piston 240A moves upward to restore to theoriginal height position. Therefore, the lens holder 2 moves upwardtogether with the support column 241 and pivotal arm 50, and the elasticseal 3 is separated from the mount 253 and adhered to the lens holdingsurface of the lens holder 2.

When adhesion of the elastic seal 3 to the lens holder 2 is ended, thepivotal arm 160 pivots through a predetermined angle, as shown in FIG.19, to move the lens holder 2 adhered with the elastic seal 4 to abovethe blocking position A6, and stops it there. When the pivotal arm 160is stopped, the air cylinder 270 is driven to move the piston rod 272upward, so the locking member 274 engages with the V-shaped groove 275of the rotation preventive member 276. As the piston rod 272 movesupward, the actuating member 273 separates from the selector valve 265.Thus, the selector valve 265 is turned off to close the high-pressurebranch pipe 259A. Also, the selector valve 258 is turned on. After that,the compressed air from the air supply source 256 flows through the port262 a of the selector valve 258, the annular groove 263 a, the port 262d, the low-pressure branch pipe 259B, the pressure reducing valve 266,the check valve 267, and the speed controller 264, and is supplied tothe upper chamber 240 a of the air cylinder 240, to move the supportcolumn 241 and pivotal arm 160 downward. Accordingly, the elastic seal 3is urged against the lens 1, thereby adhering the lens 1 to the elasticseal 3. The urging force at this time is 3 kgf/cm², as the compressedair supplied from the air supply source 256 is supplied to the upperchamber 40 a after it is reduced by the pressure reducing valve 266.

After the lens 1 is adhered to the elastic seal 3, the lens holder 2 ismoved upward to be restored. At this time, the selector valve 258 isturned off, in the same manner as in seal adhesion, and the compressedair from the air supply source 256 flows through the port 262 a of theselector valve 258, the annular groove 263 a, the port 262 e, the pipe260, and the speed controller 268, to be supplied to the lower chamber240 b of the air cylinder 240. Thus, the compressed air in the upperchamber 240 a flows through the speed controller 264, the low-pressurebranch pipe 259B, the check valve 267, the pressure reducing valve 266,the port 262 d of the selector valve 258, and the port 262 c, to beexhausted to the atmosphere from the exhaust pipe 280. For this reason,the piston 240A moves upward to restore to the original height position,and the adhering process of the lens 1 is ended.

Referring to FIGS. 4 and 5, the lens supply unit 25 holds the unexaminedlens supplied to the blocking position A6 and supplies it to the lensmeter 26. When the lens meter ends measurement of the lens, the lenssupply unit 25 conveys the lens to the blocking position A6 again. Thelens supply unit 25 has three tables movable in three orthogonaldirections (X-, Y-, and Z-axis directions) independently of each other,i.e., a Y-table 58 which is moved in the Y-axis direction by two guiderails 56 and a ball screw 57, an X-table 61 set on the Y-table 58through two guide rails 59 and a ball screw 60 so as to be movable inthe X-axis direction, and a Z-table 62 set on the X-table 61 and movablein the Z-axis direction, driving motors (not shown) for driving thesetables, and the like. The Z-table 62 has a pair of left and right hands63A and 63B, and holds the edge of the lens 1 supplied to the lenssupply unit 25 at four points with these hands. Upon receiving the lens1 supplied to the lens supply unit 25 and holding it, the pair of hands63A and 63B convey it to the lens meter 26. Measurement of the lens isperformed. When measurement is ended, the hands 63A and 63B move to thelens holding position A6 and place the lens 1 on the lens support unit145. During this period of time, the height of the concave lens surfaceof the lens is measured.

The lens meter or measuring device 26 measures the lens power, opticalcenter, cylinder axis, and the like of the unexamined lens 1 supplied tothe lens supply unit 25, performs optical layout of the lens 1, andcalculates and determines the attaching position, angle, and the like ofthe lens holder 2 with respect to the lens 1 on the basis of the lensframe shape data.

The lens measuring device 26 outputs the determined result to thecontroller.

The lens 1 measured by the lens meter 26 is conveyed to the blockingposition A6. The elastic seal 3 adhered to the lens holder 2 is urgedagainst the lens 1, as described above, so the lens 1 is held by thelens holder 2. The lens holder 2 that holds the lens 1 is conveyed tothe holder transfer position A7 upon pivot motion of the pivotal arm160, and is removed from the clamp unit 161. The lens holder 2 is thenheld by an appropriate convey robot, is conveyed to the edger, and ismounted on a clamp shaft 70, as shown in FIGS. 9 and 10. Regarding this,this embodiment performs an arris process in which the outer surface ofthe lens 1 is cut by an arris cutter 71 to form a V-shaped projection 72called an arris on the outer surface of the lens.

The lens holder 2 is mounted on the clamp shaft 70 by fitting theproximal end of the fitting shaft portion 4 in a central hole 70 a ofthe clamp shaft 70. The flange 5 of the lens holder 2 abuts against thedistal end face of the clamp shaft 70. A projecting engaging portion 73to engage with the rotation preventive portion 8 of the lens holder 2 isintegrally formed on the distal end face of the clamp shaft 70. Thisprevents rotation of the lens holder 2 with respect to the clamp shaft70. The other clamp shaft 74 is disposed on the other side of the clampshaft 70 through the lens 1 such that its axis coincides with that ofthe clamp shaft 70. An urging member 75 formed of an elastic member suchas rubber is attached to the distal end face of the clamp shaft 74 tourge the concave lens surface 1 b of the lens 1. Accordingly, the lens 1is clamped by the elastic seal 3 and urging member 75. The clamp shafts70 and 74 are rotated in directions of arrows A and B, respectively, insynchronism with cutting of the lens 1, and are simultaneously moved ina direction (Y direction) perpendicular to the axis on the basis of thelens frame shape data.

In the arris cutter 71, a cutter body 77 and four cutting edges 78attached to the circumferential surface of the cutter body 77 form amilling cutter. The arris cutter 71 is attached to a shaft 79 parallelto the clamp shafts 70 and 74. As the cutting edge 78, one formed bysintering a diamond sintered body on the surface of a chip made of,e.g., a carbide alloy, is used, and a V-shaped arris groove 84 is formedat the intermediate portion, in the widthwise direction, of its point 78a. The arris groove 84 has two types, i.e., a small arris groove and alarge arris groove. An arris angle α is about 110° to 125°. An arrisheight H is, e.g., about 0.4 mm to 0.68 mm in the case of a small arris,and is about 0.7 mm to 0.9 mm in the case of a large arris. A planingcutter may also be used instead.

The arris process of the lens performed by the arris cutter will bedescribed.

First, the lens holder 2 that holds the lens 1 is mounted on one clampshaft 70. The other clamp shaft 74 is moved forward to urge the urgingmember 75 against the concave lens surface 1 b of the lens 1, so thelens 1 is clamped by the elastic seal 3 and urging member 75. Aprocessing program is formed on the basis of the lens frame shape dataand is input to the controller of the edger.

A driving unit (not shown) is driven to rotate the arris cutter 71 inthe direction of an arrow C so the cutting edges 78 move downward fromabove. The lens 1 is rotated in the same direction as the arris cutter71 and is moved simultaneously in the direction of an arrow Y inaccordance with the processing program, so that its edge comes intocontact with the arris cutter 71. The points 78 a of the cutting edges78 bite into the edge of the lens to cut it by a predetermined depth ofcut. Finally, a lens with an outline substantially coinciding with theshape of the frame and the arris 72 on its edge is fabricated.

In the above embodiment, the rotation preventive portions 8 and 11formed on the outer surface of the lens holder 2 are grooves. However,the present invention is not limited to this, and the rotationpreventive portions 8 and 11 may be formed of projections.

In this embodiment, the curve difference between the convex lens surface1 a of the lens 1 and the lens holding surface 9 is set to at least onecurve so the lens holder 2 always abuts against the periphery of theconvex lens surface 1 a. If the curve difference is zero or is up to ±1,it can be covered by the thickness or characteristics of the elasticseal 3.

As is understood from the above description of the embodiment, accordingto the present invention, the holder holding unit 23 comprising thepivotal arm 160 and the clamp unit 161 attached to the pivotal arm 160to be vertically movable is provided. Thus, a series of the steps ofholding the lens holder 2 at the holder mounting position A4, adheringthe elastic seal 3 to the lens holder 2 at the seal adhering positionA5, and holding the lens 1 by the elastic seal 3 at the lens holdingposition A6 can be performed entirely automatically. Therefore, theburden to the operator is reduced considerably, the operating efficiencyand productivity are improved, and labor saving can be achieved. Duringthe above steps, since the operator need not hold the lens 1, the lens 1may not be soiled or damaged. Since the holder mounting position A4,seal adhering position A5, and lens holding position A6 are located onone circumference with the pivotal arm 160 as the center, a large spaceis not required, and a compact ABS can be provided.

In the above embodiment, the present invention is applied to an ABS fora single-vision lens. However, the present invention is not limited tothis, and can also be applied to an ABM for a multifocal lens.

In the above embodiment, the holder fixing mechanism 83 is constitutedby the holder fixing member 84, a spring for holding the holder fixingmember 84 in an open state, and the air cylinder 90 for operating theholder fixing member 84 and urging it against the lens holder 2.However, the present invention is not limited to this. The holder fixingmember 84 may be urged against the lens holder 2 by a spring, and thelens holder 2 held by the holder fixing member 84 may be released by anappropriate driving unit, mechanism, or the like.

According to this embodiment, in seal adhesion of urging the lensholding surface 9 of the lens holder 2 against the elastic seal 3, thusadhering the elastic seal 3 to the lens holding surface 3, the lensholding surface 9 is urged with a large urging force. Therefore, theelastic seal 3 can be reliably separated from the mount 253, and can bereliably adhered to the lens holding surface 9. In lens adhesion ofurging the elastic seal 3 adhered to the lens holding surface 9 of thelens holder 2 against the lens 1, thus adhering the lens 1 to theelastic seal 3, the elastic seal 3 is urged with an urging force smallerthan that in seal adhesion. Therefore, the lens 1 can be adheredreliably without being damaged. Also, the structure of the urging forcechange unit 255 is simple.

FIG. 21 is a view showing the schematic arrangement of anotherembodiment of the present invention.

In this embodiment, a pivotal arm 160, a clamp unit 161 attached to thepivotal arm 160 to be vertically movable, a driving motor 203 with areduction mechanism to pivot the pivotal arm 160, and an air cylinder201 for vertically moving the clamp unit 161 make up a lens holding unit23. The air cylinder 201, an air supply source 256, pipes 259 and 260, aselector valve 202 connected to the pipe 259 to which compressed air issupplied when the clamp unit 51 is to be moved downward, and the likemake up an urging force change unit 200. The flow path of the selectorvalve 202 is switched by an electrical signal from a controller.

In this urging force change unit 200, in seal adhesion, high-pressurecompressed air is supplied to the air cylinder 201, so a lens holder 2is urged against an elastic seal 3 with a large urging force. In lensadhesion, the selector valve 202 is switched by the electrical signalfrom the controller to supply low-pressure compressed air to the aircylinder 201, so the elastic seal adhered to the lens holder is urgedagainst the lens with an urging force smaller than that in sealadhesion. Therefore, the elastic seal 3 can be separated from a mount253 reliably, in the same manner as in the above embodiment, and thelens can be adhered without being damaged.

In the above embodiment, the present invention is applied to an ABS 20for a single-vision lens. However, the present invention is not limitedto this, but can also be applied to an ABM for a progressive multifocallens and a multifocal lens.

The urging force change unit 255 or 200 is not limited at all to thosedescribed in the above embodiments, but various changes andmodifications can be made. It suffices as far as the urging force changeunit can change the urging force for seal adhesion and lens adhesion.

When the holder according to the present invention is applied, theradius of curvature of the holder is selected to be larger than or equalto that of the convex lens surface of the lens, and this holder ismounted. Thus, the lens can be held in a peripheral abutting state. As aresult, a high holding force can be obtained, and holding operation isnot easily adversely affected by a mechanical vibration duringprocessing, so lens misalignment and the like can be prevented.

According to the present invention, the rotation preventive portion isformed on the outer surface of each lens holder to engage with theengaging portion of the holder storing cassette. Therefore, the lensholders are not rotated, and can be aligned in one direction and storedin the cassette.

According to the present invention, members that are colored indifferent colors for the lens types, respectively, are provided.Compared to type indication by means of an identification symbol,number, or the like, a holder can be discriminated at a glance withoutexamining it by holding it with a hand. The holder discriminationperformance can thus be improved, and the holder can be automaticallyeasily discriminated by using a sensor. Since the members are built inthe lens holder to be seen from the outside, the outer shape or size ofthe holder itself does not change. Thus, the present invention can beapplied to an existing holder as well. When storing the lens holder in acassette, a mistake of erroneously storing a different type of holdercan be prevented. When setting the cassette to an automatic centeringunit, a mistake of setting it at an incorrect position can be prevented.Since the member may be pressed into the holder by a machine ormanually, it can be built into the holder easily.

According to the present invention, a holder holding unit thatautomatically performs a series of steps of holding the lens holder,conveying the lens holder, adhering the elastic seal to the lens holder,and holding the lens by the elastic seal is provided. The lens will notbe soiled or damaged. The burden to the operator is reducedconsiderably, labor saving can be achieved, and the operating efficiencyand productivity can be improved.

According to the present invention, the elastic seal adhered to the lensholding surface of the lens holder is urged against the lens with anurging force smaller than that with which the lens holding surface ofthe lens holder is urged against the elastic seal. Therefore, adhesionof the elastic seal to the lens holder and adhesion of the lens to theelastic seal can be performed well and reliably. A damage to the lens,erroneous adhesion, and the like can accordingly be prevented. Whenadhesion is performed by the operator, the urging force may vary anddefective adhesion may occur often. However, since adhesion is performedby automatically changing and setting the urging force, the urging forcedoes not vary, and defective adhesion can be prevented.

1. A lens layout block device comprising means for adhering an elasticseal to a lens holder, means for causing said lens holder, to which theelastic seal is adhered, to hold a lens, a pivotal arm, an arm drivingunit for pivoting said pivotal arm, a clamp means attached to saidpivotal arm to be vertically movable to hold the lens holder, and aclamp driving unit for vertically moving said clamp means, wherein saidpivotal arm is pivoted to sequentially adhere the elastic seal to thelens holder and hold the lens by the lens holder.
 2. A lens layout blockdevice comprising a holder holding means for holding a lens holder at aholder mounting position, conveying the lens holder to a seal adheringposition, causing an elastic seal to be adhered to the lens holder atthe seal adhering position and conveying the lens holder to a lensholding position, and causing a lens to be held by the elastic seal atthe lens holding position, said holder holding means comprising apivotal arm, an arm driving means for pivoting said pivotal arm within ahorizontal plane, a clamp means for holding the lens holder attached tosaid pivotal arm to be vertically movable, and a clamp driving means forvertically moving said clamp unit.
 3. A lens layout block deviceaccording to claim 2, wherein said clamp means comprises a cylindricalmain body to fit on the lens holder, and a holder fixing mechanism forfixing the lens holder to the main body.
 4. A lens layout block deviceaccording to claim 3, wherein said holder fixing mechanism comprises apivotal holder fixing member, a spring for biasing said holder fixingmember in a direction to separate it from the lens holder, and a lensholder driving means for urging the lens holder into a holding position.5. A lens layout block device according to claim 2, further comprisingan arm fixing means for fixing said pivotal arm to a pivot position whensaid clamp means moves to said lens holding means.
 6. A lens holderstructure formed of a cylindrical member and having a lens holdingsurface formed of a concave spherical surface at a distal end thereof tohold a plurality of types of lenses with convex lens surfaces ofdifferent curvatures by an elastic seal adhered to the lens holdingsurface, characterized in that the plurality of types of lenses areclassified into a plurality of types of lens groups in which lenses withconvex lens surfaces of similar curvatures each form one group, and thelens holder structure comprises a plurality of types of lens holderscorresponding to the lens groups, each of the respective types of thelens holders serving to hold a lens belonging to a corresponding lensgroup with an edge of a lens holding surface thereof.
 7. A lens holderstructure according to claim 6, further comprising a rotation preventiveportion engageable with an engaging portion of a holder storing cassetteon an outer surface of the lens holder.
 8. A lens holder structureaccording to claim 6, characterized by having members built in the lensholder and colored in different colors for respective lens types.
 9. Alees holder structure formed of a cylindrical member and having a lensholding surface formed of a concave spherical surface at a distal endthereof to bold a plurality of types of lenses with convex lens surfacesof different curvatures by an elastic seal adhered to the lens holdingsurface, characterized in that the plurality of types of lenses areclassified into a plurality of lens groups in which lenses with convexlens surfaces of similar curvatures each form one group, and the lensholder structure comprises a plurality of types of lens holderscorresponding to the lens groups, each of respective types of the lensholders having a lens holding surface with a radius of curvature equalto or smaller than a minimum radius of curvature of a convex lenssurface of a lens belonging to a corresponding lens group.
 10. A lensholder structure according to claim 9, characterized by furthercomprising a rotation preventive portion engageable with an engagingportion of a holder storing cassette on an outer surface of the lensholder.
 11. A lens holder structure according to claim 9, characterizedby having members built in the lens holder and colored in differentcolors for respective lens types.
 12. A lens layout block device forurging, at a seal adhering position, a lens holding surface of a lensholder against an elastic seal, thus adhering the elastic seal to thelens holding surface, and urging, at a blocking position, the elasticseal, adhered to the lens holding surface of the holder, against a lens,thus adhering the lens to the elastic seal, characterized by having aunit for urging the elastic seal, adhered to the lens holding surface tothe lens holder, against the lens with an urging force smaller than thatwith which the lens holding surface of the lens holder is urged againstthe elastic seal.
 13. A lens layout block device according to claim 12,further having a cylinder for vertically moving the lens holder, andfluid pressure switching means for switching fluid pressure supplied tosaid cylinder during seal mounting and lens adhesion.